| Value | Category | Cases | |
|---|---|---|---|
| 2016 | 1 | 
                                    
                                    0.1%
                                 | |
| 2017 | 43 | 
                                    
                                    2.7%
                                 | |
| 2018 | 159 | 
                                    
                                    10.2%
                                 | |
| 2019 | 8 | 
                                    
                                    0.5%
                                 | |
| 9999 | NO RESPONSE | 2 | 
                                    
                                    0.1%
                                 | 
| Sysmiss | 1351 | 
                                    
                                    86.4%
                                 |